1. Field of the Invention
The present invention relates to an apparatus for the safe filing or emptying of a pressurized vessel charged with flammable and/or aggressive gas. The present invention also relates to a pressurized reactor which is charged with flammable and/or aggressive gas and is equipped with a filling lock apparatus and a corresponding de-ashing lock apparatus. In addition, the present invention relates to a special process for filling and emptying such a reactor. The present invention also relates to the use of such a reactor for the simultaneous preparation of tetrachlorosilane, trichlorosilane and hydrogen by reacting silicon with hydrogen chloride.
2. Description of the Related Art
It is known that, by reacting silicon and hydrogen chloride in an exothermic reaction, tetrachlorosilane and trichlorosilane can be prepared with the simultaneous formation of hydrogen and a production of residue in the form of ash. The reaction generally takes place at a pressure up to 3 bar absolute and a temperature of 400 to 1200xc2x0 C. Owing to legislative requirements, it is necessary to ensure that, in such syntheses, no aggressive, flammable or toxic substances escape from the plant.
For systems having hot, flammable or aggressive contents into which or out of which solids are predominantly continuously filled or withdrawn, there is no shut-off device which remains permanently sealed and reliable. Owing to deposits on sealing surfaces, as well as to mechanical or thermal stress of soft packings, the tightness of a shut-off valve can continue to be impaired.
The primary object underlying the present invention is to make the above-mentioned plants able to be operated as safely as possible.
This object is achieved according to the invention in which an apparatus for filling or emptying a pressurized vessel is charged with flammable and/or aggressive gas. The apparatus features an upper flap combination, an intermediate lock vessel having a flushing apparatus, and a lower flap combination. An above average reliable mode of operation can be ensured for reactors which are operated at atmospheric pressure or under high pressure and are charged with flammable and/or aggressive gas, in particular for those reactors for the simultaneous preparation of tetrachlorosilane, trichlorosilane and hydrogen.